In images taken by a digital camera or the like, deteriorated resolutions may frequently be observed in peripheral parts of such images. The resolution in the peripheral parts of the image taken by the digital camera or the like may be likely to be deteriorated since the field angle relies on the aberrations or the aperture sizes of a lens optical system. One of the factors of such deteriorated resolution may be mechanical vignetting. Mechanical vignetting may be observed in a part of the aperture having a large field angle in a radial direction. This part of the aperture forms an elliptic shape, thereby inducing image blurring. Thus, the resolution in the radial direction may deteriorate.
In order to overcome such deterioration of the resolution, Japanese Laid-open Patent Publication No. 2012-23498 (hereinafter referred to as “Patent Document 1”), for example, discloses an image correction technology to correct an image to adjust a change in PSF (point spread function) due to an angle of incident light by filtering the image to be processed with respect to different positions utilizing different filter data.